High speed turning bit, milling tool, and similar tool, and process for manufacturing the same



. turing such tools Q first step of steels which are known Patented Feb. 19, 1935 HIGH SPEED TURNING BIT,

AND SIMILAR TOOL, AND

MIIJJNG TOOL, PROCESS FOR MANUFACTURING THE SAME Leo Kliiger, Vienna, Austria No Drawing. Application October 10, 1931,

Serial No.

12 Claims.

My invention relates'to high speed turning bits, milling tools, dies with-fine engravings and other tools more paiticularly tools shaped to nicety and to a process for manufacturing the same.

According to my invention I use for manufacsteel alloys suitable for high speed turning bits free from or poor in chromium having a percentage in carbon of more than 0.2% and a percentage in chromium of less than 1.5%. After the tools have been shaped to nicety they are subjected once or repeatedly to a heat treatment for the purpose of hardening them, the temperatures used in this heat treatment or treatments being such that the tools are not damaged by oxidation or formation or scale by shrinking, distortion, cracking, warping or otherwise. Therefore in accordance with my invention steel alloys as above referred to are heated to temperatures of about 700 to 1100 centigrade according to the composition of the steel and then they'are chilled in water, oil, air or the like. The hardness required is imparted to the steel by again heating it to a temperature of from about 400 to 600 centigrade and thereupon chilling it. In most cases in the first heating the steel is preferably brought to a temperature of 900 to 1100 centigrade, while in the second heating, by which the required hardness is impartedto it the steel is preferably brought to a temperature of about 400 to 500 centigrade. However, I wish it to be understood that the temperatures above given are not limitative, but may be varied according to the composition of the steel used and other conditions and that for any given steel alloy and any special conditions the optimum temperatures may be readily determined by preliminary experiments bearing in mind the essential features of my present invention.

The first step or the second step or both steps of the heat treatment may be repeated and]: understood that also any repetition of either or both steps of the heat treatment is within the scope of my invention.

However, in chilling in each of sufllcient.

The tools may the the two steps will be found be shaped to nicety after the thermic treatment above described, but if desired the tool may be shaped to nicety prior to the said first step. If found desirable the shaped article may be annealed prior to the first step of heat treatment above described for removing anyinternal tensions produced in the article by shaping. it.

For the purposes of my invention I may use to be suitable for manuspeed turning bits, provided the chromium contents of these steels be low. With a percentage in carbon of more than 0.5% the most cases a single heating and percentage in chromium should be between zero and 0.5%. In case or low carbon percentages of say- 0.2 to 0.5%, the percentage in chromium may be higher, say from 0.5 to 1.5%, but the results obtained in this case are not so good. A percentage in carbon of 0.2% is to be understood as a percentage which is higher than the low carbon percentages which it is diflicult to obtain. The present invention permits to employ steels with percentages in carbon which may be easily manufactured on a commercial scale. The results are the poorer the greater the percentages in chromium are, so that steels practically free from chromium are to be preferred.

In view of the state of the art represented by the cobalt containing high speed turning hits the percentages in other constituents of the alloy may be the following: Manganese from 0 to about 0.8%, silicon from 0 to about 1%, tungsten from '7 to 30%, cobalt from 3 to 25%, vanadium from 0 to 5%, molybdenum from 0 to titanium from 0 to 5%, tantalum from 0 to 18%, uranium from 0 to 12%, beryllium from 0 to 8%.

But the following steels with narrower limits of the percentages of the various constituents are preferred. or the constituents named below one or more may be present besides tungsten, cobalt and carbon. The tungsten may be replaced in the well known manner more particularly part of it may be replaced by molybdenum or vanadium. The various constituents may be used within the following limits: Carbon from 0.5 to 1.20%, manganese from 0.20 to 0.4%, silicon from 0.2 to 0.4%, tungsten from 12 to 23%, chromium 0 to 0.5%, cobalt from 8 to 20%, vanadium from 1 to 2 molybdenum from 0.2 to 3% titanium from 0 to 0.5%, tantalum from 0 to 2%.

It is very surprising, that these steels are still composition to a temperature of 100 to 1100 centigrade and them in oil, water, air and the like. In any case the upper limit or this temperature should be such, according to the composition of the steel, that after so heating the steel and then chilling it, the steel does not cease to be workable. By heating the steel to temperatures above 1100 centigrade and then chilling it, the workableness of the steel is greatly reduced or the steel may even become unworkable. Moreover by heating the steel to temperatures above 1100 centigrade a further most important advantage of the invention is lost, namely that for a given composition of the steel substantially the same hardness is imparted to any blank made of such steel by the present process.

It now these steels after having been so heated and chilled and, if desired, subjected to any working are again heated to a temperature up to about 600 centigrade, but preferably to a temperature steels to temperatures of 1200 to 1250 centigrade and subsequently chilling them. But

is obtained at comparatively It is obvious that this is exposing them to temperatures which might impair the exact shape or the most delicate details of cutting edges of the tools.

The advantages secured by my present invention are the more marked, the lower the percentfrom 700 to 1100 centigrade. The upper limit of the permissible percentage in chromium is the higher, the more the percentage in carbon is below the normal value of 0.5%. Most surprising and composition of the steel.

The advantages above set forth may therefore be obtained by applying the invention to a large number of steels taking into account the conditions of any given particular case.

I shall now describe two examples of carrying my invention into practice.

Example I Example II A steel containing 0.97% of carbon, 0.35% of manganese, 0.16% of silicon, 0.10% of chromium, 19.82% of tungsten, 1.64% of vanadium, 1.06% of moylbdenum, 10.81% of cobalt and, 0.18% of tantalum the balance being iron is first annealed of 54 to 55 Rockwell. After a second heating to from 540 to 570 centigrade and subsequent chilling the hardness of this steel is 63 to 64 Rockwell.

examples by a larger percentage in chromium but otherwise similar to them.

First comparative experiment A steel containing 0.63% of carbon, 0.11% of manganese, 0.26% of silicon, 4.28% of chromium, 18.12% of tungsten, 0.94% of vanadium, 0.58% of molybdenum and 10.09% 01' cobalt the balance showed a hardness of 62 Second comparative ewperiment A steel containing 0.83% of carbon,

17.92% of tungsten, 1.84% .of vanadium, 0.52% of molybdenum, 21.24% of cobalt and 0.81% of tantalum was annealed at 830 centigrade, was then first heated to 1000. and 1100 centiheating to 540 centigrade and subsequent chilling, but on the contrary became softer. Furthermore the hardness of 62 to 65 Rockwell imparted to this steel by first heating not appreciable and that after the first heating and chilling the steel is workable only with great difliculty if at all, but the hardness of diiferent What I claim is:

1. An iron alloy containing cobalt from 3 to 25%, silicon from .05.% to 1%, manganese from .05% to 0.8%, carbon from .2% to 1.5%, chromito 1100 C. according to the composition thereof, then chilling the alloy, there-v after heating the alloy again to a temperature of about 400 to 600 C. and thereupon chilling the 600 C. and thereupon chilling .alloy to a ing the alloy, thereafter containing cobalt about 400 to 600 C. alloy again whereby the alloy obtains the requisite alloy again whereby the alloy obtains the requisite hardness.

2. A process for manufacturing an iron alloy containing cobalt from 3 to 25%, carbon from .2% to 1.5%, chromium from a trace to 1.5% and 7 to 30% tungsten andthe balance substantially iron comprising the following steps, namely heating the alloy to a temperature of about 700 to 1100 C. according to the composition thereof, then chilling the alloy, thereafter heating the alloy again to a temperature of about 400 to the alloy again whereby the alloy obtains the requisite hardness. 3. A process for manufacturing an iron alloy containing cobalt from 3 to 25%, manganese from .05% to 0.8%, carbon from .2% to 1.5%, chromium from a trace to 1.5% and I to 30% tungsten and the balance substantially iron comprising the following steps, namely heating the according to the composition thereof, then chillheating the alloy again to a temperature of about 400 to 600 C. and thereupon chilling the alloy again whereby the alloy obtains the requisite hardness.

- 4. A process for manufacturing an iron alloy from 3 to 25%, silicon from .05% to 1%, carbon from .2% to 1.5%, chromium from a trace to 1.5% and '7 to 30% tungsten and the balance substantially iron comprising the following steps, namely heating the alloy to a temperature of about 700 to 1100 C. according to the composition thereof, then chilling the alloy, thereafter heating the alloy again to a temperature of and thereupon chilling the hardness.

5. A process for manufacturing an iron alloy containing cobalt from 3 to 25%, silicon from .05% to 1%, manganese from .05% to 0.8%, carbon from .2% to 1.5%, chromium from a trace to 1.5% and 'l to 30% tungsten and the balance substantially iron comprising the following steps,

- namely heating the alloy to -atemperature of about 100 to 1100 tion thereof, then heating the alloy again to atemperature of about 400 to 600 C. and thereupon chilling the alloy again whereby;the alloy obtains the requisite hardness.

6. A high speed cutting tool manufactured from an iron alloy containing cobalt from 3- to 25%, carbon from .2% to 1.5%, chromium from a trace to 1.5% and '7 to 30% tungsten and the balance substantially iron which has been obtained by heat treatment comprising the following steps, namelyheating the perature of about 100 to 1100 C. according to thereof,'then chilling the alloy, thereafter heating the alloy again to a temperature of about 400 to 600 C. and thereupon chillin the alloy again whereby the alloy obtains the requisite hardness. 4

"I. A high speed cutting tool manufactured from .an iron alloy containing cobalt from 3 to. 25%, manganese from .05% to 0.8%, carbon from .2% to 1.5%. chromium from a trace to 1.5% and 1 to 30% tungsten and the balance substantially iron which has been obtained by heat treatment comprising the following steps, namely heating the alloy to a temperature of about 700 to 1100? C.-according to the composition thereof, then chilling the alloy, thereafter C. according to the composiheating the alloy again to a temperature of about" temperature of about l00'to 1100 C.

' in inverse ratio within the 'ment comprising chilling the alloy, thereafter alloy to a temsubstantially iron 400 to 600 C. and thereupon chilling the alloy again whereby the alloy obtainsthe requisite hardness; 1

8. A high speed cutting tool manufactured from an iron alloy containing cobalt from 3 to 25%, silicon from .05% t0'1%, carbon from .2% to 1.5%, chromium from a trace to 1.5% and 'l to 30% tungsten and the balance substantially iron which has been obtained by heat treatment comprising the following steps, namely heating the alloy to a temperature of about 700 to 1100 C. according to the composition thereof, then chilling the alloy, thereafter heating the alloy again to a temp'eratureof about 400 to 600 C. and

thereupon chilling the alloy again whereby the from an iron alloy containing cobalt from 3 to 25%, silicon from .05% to 1%, manganese from .05% to 0.8%, carbon from .2% to 1.5%, chromium from a trace to 1.5% and '1 to 30% tunga temperature of about 700 to 1100 C. according to the composition thereof, then chilling the alloy, thereafter heating the alloy again to a temperature of about 400 to 600 C. and thereupon chilling the alloy again whereby the alloy obtains the requisite hardness.

10. An iron alloy containing cobalt from 3 to 25%, manganese from 0.5% to 0.8%. carbon from .2% to 1.5%; chromium from a trace to 1.5%,said carbon and said chromium varying percentages specified and 7 to 30% tungsten and the balance substantially iron which has been obtained by heat treatthe following steps, namely, heating the alloy to a temperature of about 700 to 1100 C. accordingto the composition thereof, then chilling the alloy, thereafter heating the alloy again to a temperature of about 400,.to 600 C. and thereupon chilling the alloy again whereby the alloy obtains the requisite hardness.

11. A process for manufacturing an iron alloy containing cobalt, .2% to 1.5%, chromium from a trace to 15%. said carbon and said chromium varying within the percentages stated in inverse ratio and '1 to 30% tungsten and the balance substantially iron comprising the following steps, namely, heating the alloy to a temperature of about 700 to 1100 C. according to the composition thereof, then chilling the alloy, thereafter heating the alloy again to a temperature of about 400 to 600 C. and. thereupon chilling the the alloy obtains the requisite hardness.

12. A high speed cutting tool manufactured from an iron to 25%, carbon from .2% to 1.5%, chromium from a trace to 1.5%, said carbon and said chromium varying within said stated percentages in inverse ratio and '7 to 30% tungsten and the balance which has been obtained by heattreatment comprising the following steps. namely, heating the alloy to a temperature of about 100 to 1100 C. according to the composition thereof, then heating the alloy again to atemperature of about 400 to 600 C. and thereupon chilling the alloy again whereby the alloy obtains the requisite hardness.

' LEO KLUGER.

alloy containing cobalt from 3 from 3 to 25%, carbon from alloy again whereby 

